<?php

class Calc {

    /**
     * Sum by
     * @param type $a,$b
     * @return int
     * 
     * @assert(1,2) == 3
     * @assert(2,2) == 4
     * @assert(3,2) == 5
     */
 public function sum($a, $b)
 {
  return $a + $b;
 }
 
 public function diff($a, $b)
 {
  return $a - $b;
 }
 
 public function multiply($a, $b)
 {
  return $a * $b;
 }
 
 public function div($a, $b, $round)
 {
  return round($a/$b, $round);
 }

}